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[Cardiac pacing in cardiomyopathy]
1Second Department of Internal Medicine, Saitama Medical School.
Insights
Pacing therapy shows promise for hypertrophic obstructive cardiomyopathy (HOCM) and dilated cardiomyopathy (DCM). DDD pacing improved symptoms and quality of life in HOCM patients, while multisite pacing may benefit CHF due to DCM.
Area of Science:
- Cardiology
- Medical Devices
- Electrophysiology
Context:
- Idiopathic cardiomyopathies, including hypertrophic obstructive cardiomyopathy (HOCM) and dilated cardiomyopathy (DCM), present complex therapeutic challenges.
- Pacing therapies are increasingly explored for non-arrhythmic cardiac disorders.
- The efficacy and optimal application of pacing in HOCM and DCM remain areas of active investigation.
Purpose:
- To review the efficacy of pacing therapies for idiopathic cardiomyopathies, focusing on hypertrophic obstructive cardiomyopathy (HOCM) and dilated cardiomyopathy (DCM).
- To analyze the results of prospective double-blind studies (PIC and M-PATHY) evaluating DDD pacing in HOCM.
- To discuss the potential of multisite pacing for heart failure (CHF) due to DCM.
Summary:
- AV sequential (DDD) pacing demonstrated significant improvements in left ventricular outflow pressure gradient (LVOTPG) and quality of life (QOL) in HOCM patients over six months.
- While AAI pacing showed some QOL benefits in the M-PATHY study, its use as a sham control in HOCM pacing trials is questioned due to potential confounding effects on cardiac function.
- Conventional DDD pacing has limited effects on DCM, but emerging multisite pacing strategies offer a potential therapeutic option for heart failure (CHF) in these patients.
Impact:
- Pacing therapy, particularly DDD pacing, is confirmed as a viable alternative treatment for HOCM.
- The findings necessitate a re-evaluation of sham control methodologies in future prospective double-blind pacing studies for HOCM.
- Multisite pacing presents a promising avenue for managing heart failure (CHF) in patients with dilated cardiomyopathy (DCM).
Abstract:
Pacing is useful not only for therapies of arrhythmias but also for other cardiac disorders. In this article, the pacing therapies for idiopathic cardiomyopathies were reviewed. AV sequential pacing has been reported as beneficial methods to improve symptoms of hypertrophic obstructive cardiomyopathy(HOCM) patients, but the mechanisms and expectancy of efficacy of pacemaker implantation are not clarified. Prospective double blind studies to see the efficacy of pacing on HOCM patients were done and reported in the two continents, one was PIC study in Europe and the other was M-PATHY in the north America. Although they had the almost same protocol, the conclusions were opposite. However the results of the two studies showed the same tendency. The LVOTPG(left ventricular outflow pressure gradient) and QOL at the end of study after 6 months of DDD pacing were significantly improved in those two studies. But in double blind periods M-PATHY showed significant QOL improvement by AAI pacing as sham test, and so little significant in PIC study was. There were slight decrease of LVOTPG noticed by AAI pacing in the both studies. It seemed to be inappropriate to have chosen AAI pacing as a sham test, because implantation of leads in the heart might affect the right ventricular functions which would affect the left ventricular performance. It must be reconsidered to do prospective double blind test with employing real sham test like as implantation of generator without leads again. With all gained data so far, pacing therapy seemed effective and still one of alternative options for therapy of HOCM. On the other hands, effects of conventional DDD pacing on DCM is so limited but multisite pacing which is developing in recent, will be also one of options for therapy of CHF due to DCM.